1. Field of the Invention
This invention relates to ground anchors, and more specifically to driven pivoting ground anchors.
2. General Background
Ground anchors, or earth anchors, of the driven and pivoting or tilting type are well known and generally include a main body portion having a leading edge adapted to be driven into the ground, a trailing edge including an outturned lip and a cable or rod or guide wire attachment point intermediate the leading and trailing edges generally positioned from about the midpoint of the overall length of the anchor or towards the trailing edge so that upon exertion of the force on the cable or attached rod or guide wire, after insertion of the anchor into the ground, the trailing edge's outturned lip will bite into the earth, causing the anchor to rotate or pivot to a locked position generally at a right angle to the withdrawal force.
Widely currently used driven pivoting anchors of the type described are available from the assignee of this application under its Duckbill trademark and generally employ a somewhat cylindrical main body portion having an attachment point intermediate its ends and having at its forward end a plurality of forwardly extending guiding plane surfaces which terminate in chiseled edges. The cylindrical body shaped member, at its trailing end, has a bore extending into the body of the cylindrical member for receipt of a drive rod for driving the anchor into the earth and is provided with an outturned lip on a side of the cylindrical body portion opposite the side having the cable or guide wire attachment point.
Such anchors are shown, for example, in U.S. Pat. Nos. 4,044,513 and 4,096,673, both of which are assigned to the assignee of this application. Improvements of such anchors are well known and include, for example, applicant's pending Design application No. 29/270,187, now Pat. No. D572546 issued Jul. 8, 2008 and U.S. Utility application Ser. No. 11/803,138 filed May 14, 2007, now U.S. Pat. No. 7,534,073 issued May 19, 2009.
Other variants of such anchors are sold, for example, by Foresight Products, LLC under trademarks Manta Ray and Stingray and employ extensive side projecting wings that extend backwardly and outwardly from the leading edges to a greater or lesser degree and provide greater resistance to withdrawal of the anchor after the anchor has been driven into the ground and rotated to the point where the wings lie substantially normal to the tension direction of the cable.
While such anchors, both of the wingless, small-winged and large wing design, have found successful utility in many applications, including use in connection with revetment and soil retaining mats. However, the chiseled or sharpened leading edges which facilitate penetration into the ground can, in certain instances, cause damage to certain types of soil retaining mats which are commonly used in turf reinforcement and ground stabilization. Such mats, often known as High Performance Turf Reinforcement Mat (HPTRM) of the type available under the mark Pyramat from Propex, Inc. or of the type shown, for example, in U.S. Pat. No. 5,616,399 entitled “Geotextile Fabric Woven or a Honeycomb Weave Pattern and having a Cuspated Profile after Heating,” may consist of individual strands essentially woven together and formed or fused to provide the mat. The strands are generally manufactured of plastics material. Other fabric-like woven mats utilizing similar or different materials are also known, as are non-woven mats. Where it is desired to anchor such mats to the underlying soil, the use of the previously known driven pivoting anchors can cause damage to the mat, particularly since the chiseled or sharpened leading edges will have a tendency to cut through the material of the mat, thereby weakening the mat.
It would therefore be an advance in the anchoring field to provide an anchor suitable for use with such turf reinforcement mats which could be driven through the mat with a reduced likelihood of damage to the mat.